Thank you very much for your prompt reply.
Regarding 2: I want because it occupied a huge disk space.
Actually I'm intrested in a tiny program that frees up/clears... AUTOMATICALLY
i) SYSTEM CACHE
ii) PROCESS KILLING; that are not in use
Presently I'm using a program (RegToy) to do the same but it's not a standalone program rather a group of many programs/features.